Study On The Systems Of LNBR/Epoxy Resin Composites

In this paper, LNBR/EP composite materials were prepared by physical blending methods, while the liquid nitrile rubber (LNBR) was used as a toughening agent for modifying the toughness of epoxy resin. And the effect of curing agents and amount of LNBR to the mechanical properties and thermal stability of LNBR/EP composite were investigated. Meanwhile, the amount of curing agent and accelerator were determined by isothermal differential scanning calorimetry (DSC). Further more, the curing reaction and curing kinetic of composite curing system were also investigated, the kinetic equation was deduced, and the optimum curing process parameters was determined by non-isothermal DSC. In addication, the curing mechanism was investigated by Fourier Transform Infrared Spectroscopy (FT-IR). LNBR/nSiO2/EP composite was prepared, while the silicon nanoparticles (nSiO2) were used as a toughening agent for two-component toughening epoxy. The mechanical properties and thermal stability of LNBR/nSiO2/EP composite were studied. LNBR/EP-CF composites were prepared reinforcing LNBR/EP composite by filling the acid and silane coupling agent modified carbon fiber (CF).The experiment for LNBR/EP composites showed that has the robost mechanical properties impact strength (23.6KJ/m2), tensile strength (60.3MPa) and elongation at break (26.32%) of the LNBR/EP composite are obtained. However, the temperature Tg of the LNBR/EP composite decreases from 122.2℃ to 84.4℃ with amount of LNBR increases; And the thermal stability decreases and the toughness increases for composite material.The optimum amount of curing agents MeTHPA (70%) and accelerator DMP-30 (1%) are determined from MeTHPA/DMP-30/EP curing system researched by isothermal DSC. The experimental results showed that the curing reaction activation energy is 68.102KJ/mol and reaction order n (0.94) is obtained by non-isothermal DSC, as well as the frequency factor A (1.314×108) and curing reaction kinetics equation; The optimum curing process conditions were 130℃/4h which obtained by fit curve extrapolated form temperature parameter through non-isothermal DSC.LNBR/nSiO2/EP composites were prepared from the epoxy toughened by LNBR and nSiO2 surface modified by KH-560. As the amount of LNBR stabilized at 20phr, the tensile strength of the composites increases to 68.4MPa. When the amount of nSiO2 reach to 2.0phr; And the impact strength and elongation at break of the composite material were attain to 28.1KJ/m2 and 28.27%. When the amount of nSiO2 reach to 3.0phr, the Tg temperature of LNBR/nSiO2/EP composites increases from 92.9℃ to 109.2℃, while the amount of carbon residue and the temperature of maximum thermal decomposition rate increases with the amount of nSiO2 increased from 0 to 5.0phr, The thermal stability and toughness of LNBR/nSiO2/EP composite material increases.The enhanced LNBR/EP-CF composites were prepared by carbon fiber (CF) surface-modified by strong acids and KH-560. When the amount of CF reach to 1.0phr, the impact strength, tensile strength and elongation at break of LNBR/EP-CF composites were attain to 23.6KJ/m2,65.1MPa and 25.64%. While the Tg increases from 92.9℃ to 95.3 ℃, and the thermal decomposition temperature increases from 400.75℃ to 406.02℃.